The biomolecular reactivity of gas phase dications
This thesis reports the results of experiments investigating the reactivity of gas phase dications in collisions with neutral molecules at collision energies between 1eV and 14 eV in the laboratory frame using crossed beam techniques. Product ion intensities are measured using time of flight mass spectrometry and integral reaction cross sections are extracted from raw data for the various reaction channels. Also contained within this thesis are details of the experimental apparatus and data reduction methods along with relevant theoretical aspects of the reactions. The collision system CFn2+ + H2X (n = 1,2 and X = S, O) is shown to exhibit both dissociative and non-dissociative electron transfer reactivity which is examined using a model based on the Landau-Zener theory. Previously unobserved bond forming reactions are also observed. Mechanisms, involving a sequential process of adduct formation, charge separation and fragmentation, are proposed for these bond forming reactions. The collision system Ar2+ + NH3 exhibits both electron transfer and bond forming reactivity. Again, electron transfer reactivity is rationalised using the Landau-Zener theory. A mechanism is proposed for this previously unobserved bond forming reaction.